Global light transport describes the complex ways in which light interacts with objects, such as inter-reflections and scattering. In computer graphics, global light transport is used to provide scenes with visually rich shading effects for photorealistic rendering of scenes. The shading detail from global light transport arises from light that reflects off surfaces in a scene. This reflected light, known as indirect illumination, may be computationally intensive to render because of the many light bounces that may be simulated as part of the scene. Thus, rendering of indirect illumination is difficult to achieve on most computing devices because of the large amounts of computing resources (e.g., cores/processors, storage memory, and the like) that are required to compute and/or store the indirect illumination.
There are several challenges to rendering indirect illumination. One challenge is handling dynamic scenes with local light sources. Traditional techniques may be impractical for handling dynamic scenes with local light sources because of the prohibitive costs of storing the pre-computed light transport (e.g., typically several hundred megabytes) for each scene configuration. Another challenge is dealing with the multiple bounces of interreflected light as it travels through the scene. Each additional bounce in each light path that is rendered adds to the computational requirements.